Transformer cooling apparatus



Sept. 16, 1969 c. D. WARE 3,46YJ 78 TRANSFORMER COOLING APPARATUS FiledDec. 27, 1966 2 Sheets-Sheet 1 INVENTOR. CHESTER D. WARE BY MM 0 WATTORNEY Sept. 16, 1969 c. D. WARE 3,457,178

TRANSFORMER COOLING APPARATUS Filed Dec. 27, 1966 2. Sheets-Sheet 2FIG.3

l N VENTOR. CHESTER D- WARE BYM U. W

ATTORNEY United States Patent Office 3,467,178 Patented Sept. 16, 19693,467,178 TRANSFORMER COOLING APPARATUS Chester D. Ware, La Crosse,Wis., assignor to The Trane Company, La Crosse, Wis., a corporation ofWisconsin Filed Dec. 27, 1966, Ser. No. 604,989 Int. Cl. H01f 27/10;F28d /00 US. Cl. 165-107 4 Claims ABSTRACT OF THE DISCLOSURE Transformercooling apparatus including means for pumping transformer fluid from thetransformer and back to the transformer through a circuit containingparallel paths one of which contains a heat exchanger in which heat istransferred to a heat sink such as air by forced convection of airthrough the heat exchanger.

Transformers require a relatively large flow of cooling fluid throughthe transformer in order to prevent certain areas from reaching anexcessive temperature. If all of the cooling fluid is circulated throughthe heat exchanger, the total cross-sectional flow area of the tubesmust be large and the size of the headers must also be large. Theserequirements make the heat exchanger generally large and expensive.

It is therefore an object of this invention to provide transformercooling apparatus having a more eflicient lower cost heat exchanger bypassing some of the cooling fluid around the heat exchanger and thusmaintaining the flow required in the transformer.

With a construction in which some of the cooling fluid is bypassedaround the heat exchanger, the pump operates against a lower head withrespect to the bypassed fluid.

It is therefore one of the objects of this invention to provideapparatus which permits the use of a lower cost motor and which alsoresults in lower power requirements.

It is another object of this invention to provide transformer coolingapparatus having a pump for proportioning the flow through the heatexchanger and the flow around the heat exchanger.

It is still another object of the invention to provide in transformercooling apparatus a simple system in which only the cooled fluid pumpedis passed through the motor to cool the same.

Other objects and advantages of the invention will become apparent asthe specification proceeds to describe the invention with reference tothe accompanying drawings in which:

FIGURE 1 is a side elevational view of a transformer and coolingapparatus connected thereto;

FIGURE 2 is a sectional view taken substantially on line 22 of FIGURE 1with the pump shown in section;

FIGURE 3 is a sectional view of a modification of the invention takensubstantially on line 22 of FIGURE 1.

Referring now to FIGURE 1, a transformer 10 has a conduit 12 forconducting cooling fluid to the inlet header 14 of a heat exchanger 16.Heat exchanger tubes 18 conduct cooling fluid from inlet header 14 tooutlet header 20. Fins 22 are secured to tubes 16 to increase the heattransfer.

A motor 24 drives a fan 26 which moves air through the casing 28 andover the coil 16 to cool the cooling fluid flowing in the coil.

A pump 30 is driven by a motor 32. The shaft 33 of the motor 32 extendsthrough the end wall 34 of the motor and into the housing 36 of the pump30. An impeller 38 is secured on the shaft 33 to rotate therewith.

Impeller 3-8 has a first annular passageway 40 with blades therein and asecond annular passageway 42 with blades therein. Passageway is in fluidcommunication with header 20 to receive cooling fluid therefrom andpassageway 42 is in fluid communication with conduit 44 which receivescooling fluid from conduit 12.

Housing 36 has a volute discharge chamber 46 in which the cooled fluidfrom header 20 and the bypassed cooling fluid from conduit 44 arepartially mixed. Volute chamber 46 is connected to discharge the coolingfluid into a conduit 48 which conducts it to the transformer 10.

The motor 32 is cooled with the cooling fluid of the system as will nowbe described. A conduit 50 is in fluid communication with volutedischarge chamber at a location to intercept fluid from passageway 40which conducts the cooled fluid from the heat exchanger. This cooledfluid flows from conduit 50 into the motor 32 to cool the motor 32. Thisfluid then passes from the motor to annular passageway 52 in impeller 38and then through one or more holes 54 to the suction inlet side of'impeller 38. Although it is preferred to use the cooled cooling fluidfor motor cooling, it should be understood that a mixture of the cooledcooling fluid and the bypassed cooling fluid could be used and the motorcould even be cooled by using all bypassed cooling fluid provided thatthe motor is designed for high temperature operations.

Referring now to FIGURE 3 it can be seen that the construction is quitesimilar to that of FIGURES 1 and 2 except that in this case the pumpimpeller has the passageways in back to back relationship. The pump 56of FIGURE 3 has a casing 58 and is driven by a motor 60 which has ashaft 62 extending into the pump casing 58 and supporting an impeller64.

Impeller 64 has a first annular passageway 66 with blades therein and asecond annular passageway 68 with blades therein.

Passageway 66 is in fluid communication with header 20 to receive cooledcooling fluid therefrom, and passageway 68 is in fluid communicationwith bypass conduit 70 to receive cooling fluid therefrom. Bypassconduit 70 is connected to receive cooling fluid from conduit 12.

Pump 56 has a volute discharge chamber 72 which receives fluid from bothpassageways in impeller 64 and discharges the fluid into conduit 48 forflow to transformer 10.

Motor 60 receives cooling fluid from conduit 74 which is connected tovolute discharge chamber 72 in the plane of the outlet of passageway 66in order that the fluid entering conduit 74 may be substantially allcooled cooling fluid. Cooling fluid leaves the motor and enters the pumpthrough opening 76. As explained with reference to FIGURE 2, it ispreferred that the fluid conducted to the motor for motor cooling besubstantially all cooled cooling fluid, however it is possible to use amixture of cooled and bypassed cooling fluid or even all bypass fluidunder certain conditions.

While I have described the preferred embodiments of my invention, Icontemplate that many changes may be made without departing from thescope or spirit of my invention and I desire to be limited only by theclaims.

I claim:

1. Apparatus for cooling a transformer comprising a first conduit forconducting fluid from and to a transformer in a closed circuit, a heatexchanger in said first conduit, means for forcing a heat exchange fluidover the outside of said heat exchanger to cool said heat exchanger, asecond conduit in fluid communication with said first conduit andbypassing said heat exchanger, a pump, a motor for driving said pump,said pump being connected in fluid communication with said first andsecond conduit to move fluid through said first and second conduits,said pump having a centrifugal impeller with a first passageway insuction fluid communication with said heat exchanger and a secondpassageway in suction fluid communication with said bypass conduit.

2. Apparatus of claim 1 including a third conduit extending from thedischarge side of said centrifugal impeller to said motor for conductingfluid to said motor to cool said motor, means for conducting fluid fromsaid motor to said conduit at a point upstream from the discharge sideof said pump.

3. Apparatus of claim 2 in which said centrifugal impeller is arrangedwith said first and second passageways nested one within the other, saidpassageways in common discharge fluid communication.

4. Apparatus according to claim 2 in which said centrifugal impeller isarranged with said first and second passageways back to back, saidpassageways in common discharge fluid communication.

References Cited UNITED STATES PATENTS Schruder 165-35 Hess et a1.103-87 X Paluer 165-107 X Peckham et al. 103-103 X Dunn et al. 103-87 XRobins-on 165-108 White 103-87 X White 103-87 X ROBERT A. OLEARY,Primary Examiner THEOPHIL W. STREULE, Assistant Examiner US. Cl. X.R.

